Throttle Body Actuator or Fuel pressure Regulator?

Post by **shiloh51933** » 06 Apr 2017, 12:36

2004 XC70 w/200k on odo, we use only 93 octane fuel, Liqui Moly 5w40 full synthetic/Mann filter, new Bosch spark plugs and new coil packs, timing belt was changed about a year ago w/new tensioner, new idler pulley all Volvo parts. Anyway she has been running rough with misfire on cylinder #3 & #5. So I started running diagnostics on the ignition system, fuel and vacuum...ignition system looked good so I moved onto fuel system. Fuel pump is fully functional as far as I can tell, testing the fuel pressure at the fuel rail was leading me to believe I could possibly have an issue w/FPR. I believe the FP(fuel pressure) on a '04 XC70 should be about 57psi because of the turbo. The fuel pressure was around 57psi but erratic going back and forth between 55psi & 60psi rapidly. So I was thinking possibly the FPR(FP regulator) could be cause of this unless there's a blockage in the fuel return line. So I pour some techron fuel treatment into gas tank, start her up then run for little bit then give her some throttle and it started to clear up quite a bit. I shut her off for about 15 minutes then go to start her up to test drive her but on start up she's running rough again so I go to give her throttle but she won't go over 2000rpm. Performance issue prompts on cluster screen along with "CEL", DTC p2111 stuck open throttle. So I erase that code and she starts up and runs good but not perfect, she had a blip every so often at this point while running at operating temp. Now on a cold start she runs terribly rough w/fuel pressure going crazy between 55psi and 60psi. When I shut the motor down she holds fuel pressure normally, so it doesn't look like it got a leak in the system. Now I know the earlier model V70XC had some issues with the electronic throttle body but as far as I know that issue was resolved and that the newer ETB was much better. Anyway, sorry for the long read but I wanted to make sure I covered everything.

Post by **chrism** » 06 Apr 2017, 13:49

Have you cleaned out the throttle body?

I while back I went down this road with my wife's 05 S80 2.5T. It was throwing throttle related codes, displaying "Reduced Engine Performance", and going into limp mode. I cleaned the throttle body - no fix. I verified a good clean wiring connection at the throttle body - no fix. I REPLACED the throttle body with a brand new one - no fix. Unlatched and reinstalled the ECM - problem FIXED? If the throttle control wiring gets dirty/corroded at the ECM connector pins, then apparently the OBD can't really tell exactly where the break is, just that there is a failure "somewhere" in the throttle circuit.

BTW - the indy Volvo mechanic I talked to said that after all of the Volvos they have troubleshot, he has NEVER seen a Bosch throttle module go bad.

Post by **oragex** » 06 Apr 2017, 15:53

2004 is the first year with CEM water ingress. Look at the module, if it got water it will show traces of water on the box (check out youtube)

Post by **shiloh51933** » 08 Apr 2017, 09:29

oragex wrote: ↑06 Apr 2017, 15:53 2004 is the first year with CEM water ingress. Look at the module, if it got water it will show traces of water on the box (check out youtube)

What ? haven't heard about this.
I have a scanner that can also give me the manufacturer codes and I when I put in oem specific mode I'll get a C928 code which has something to do with CEM. I have to download the Volvo software onto this newer scanner because the scanner will only define the Generic DTC's. I'll definately try youtube. Thank you.

Post by **shiloh51933** » 08 Apr 2017, 10:15

chrism wrote: ↑06 Apr 2017, 13:49 Have you cleaned out the throttle body?

I while back I went down this road with my wife's 05 S80 2.5T. It was throwing throttle related codes, displaying "Reduced Engine Performance", and going into limp mode. I cleaned the throttle body - no fix. I verified a good clean wiring connection at the throttle body - no fix. I REPLACED the throttle body with a brand new one - no fix. Unlatched and reinstalled the ECM - problem FIXED? If the throttle control wiring gets dirty/corroded at the ECM connector pins, then apparently the OBD can't really tell exactly where the break is, just that there is a failure "somewhere" in the throttle circuit.

BTW - the indy Volvo mechanic I talked to said that after all of the Volvos they have troubleshot, he has NEVER seen a Bosch throttle module go bad.

Only thing is that I've been only getting random/misfire codes and an emission code. It wasn't until I really got on the throttle while trying to diagnose the fuel system that I got the P2111 for stuck open throttle plate. After resetting everything the P2111 went away(throttle safety governor mode) and she has done this once or twice b4, will suddenly run poorly and run good after shut down then restart. With that said I'm more than willing to try your suggestion. The TPS(throttle position sensor) could also be faulty, giving the ECU false information.

So all you did was remove the ECM from the box under the hood? Just unlatch the ECM then pull it out and reinstall as you found it? You didn't try to clean the contact points or anything?